We use radioimmunoassay to provide data on female hormone metabolism in normal human beings from birth through adolescence, and to study conditions in which the production of estrogens is abnormal in either timing or amount. Because circulating dialyzable (free) estrogen is metabolically active, and the fraction circulating in association with sex hormone binding globulin is inactive, we have used equilibrium dialysis to quantitate the percent and concentration of dialyzable estradiol in serum. A method for urinary estrone and estradiol glucuronide conjugates was developed. A technique for quantitating urinary free estradiol will be developed. The appearance of estrogen receptors during growth and development will be evaluated. Bibliographic references: 1. Angsusingha, K., Kenny, F.M., Nankin, H.R., and Taylor, F.H. Unconjugated Estrone, Estradiol and FSH and LH in Prepubertal and Pubertal Males and Females. J. Clin. Endocr. Metab. 39: 63-68, 1974. 2. Kenny, F. M., and Angsusingha, K. Radioimmunoassay of Circulating Unconjugated Estrogens During Growth and Development in Normal and Abnormal Conditions. In Nuclear Medicine in Vitro. B. Rothfeld, Editor, J. B. Lippincott Co., Philadelphia, Pa. 1974, pp. 150-163. 3. Kenny, F.M. Delayed and Precocious Puberty. In Pediatrics, Ziai, M., Janeway, C.A., and Cooke, R.E., Eds. Little, Brown and Company, Boston (in press). 4. Kenny, F.M., Radfar, N., Angsusingha, K., and deLevie, M. Radioimmunoassayable Serum and Urinary Estrone and Estradiol and Percent of Dialyzable Estradiol from Infancy Through Adolescence; Evidence for Activity of the Prepubertal Ovary. Presented at the Endocrine Society, Atlanta, Georgia, June 12, 1974. Abstract. 5. Klein, A.H., Radfar, N., and Kenny, F.M. Estradiol (E2) Levels in Umbilical Cord Plasma: Correlation with Mode of Delivery and Fetal Sex. Implications Regarding Mechanisms of Labor. To be presented at The Society for Pediatric Research, Denver, Colorado, April 19, 1975. Abstract in Pediatric Research 9:291, 1975.